Engine oil degradation judging method and apparatus

• US 6,578,412 B2
• Filed: 03/13/2002
• Issued: 06/17/2003
• Est. Priority Date: 03/16/2001
• Status: Expired due to Term

• Current Assignee: Isuzu Motors Limited
• Original Assignee: Isuzu Motors Limited
• Inventors: Ishibashi, Yasutaka, Matsumoto, Syunji, Konno, Atsushi
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): Mack, Corey D.
• Application Number:
  US10/096,113
• Publication Number:
  US 20020129645A1
• Time in Patent Office: 461 Days
• Field of Search: 73/350.2, 731/16, 731/172, 731/181, 73/530.5, 340/450, 340/450.3, 340/438, 340/441, 340/451
• US Class Current: 73/114.55
• CPC Class Codes: F01M 1/18 Indicating or safety devices concerning lubricant level F01M11/06, F01M11/12
• CPC Class Codes: F01M 2011/14 for indicating the necessity to change the oil
• CPC Class Codes: F01M 2011/1466 by considering quantity of soot

Abstract

A method of determining a degree of oil degradation in the diesel engine depending on an injection end point in such an injection way as to cause the injection 0end point to be earlier that a specific point (T_B) and depending on the injection amount after the specific point and the injection end point in such an injection way as to cause the injection end point to be later than the specific point. In every fuel injection, it is judged whether the injection end point is set before or after the specific point, and a current injection degradation value is obtained by using a corresponding map. A cumulative added value is obtained to judge the oil degradation.

Claims

1. A judging method of engine oil degradation to be carried out by obtaining an amount of soot generation in a diesel engine, comprising:

judging whether a fuel injection end point is set before or after a predetermined oil degradation degree dispersion point in every fuel injection operation to be performed;

calculating an oil degradation value in a current performed fuel injection operation by using the fuel injection end point when the fuel injection end point is set before the predetermined oil degradation degree dispersion point;

calculating an oil degradation value in the current performed fuel injection operation by using the fuel injection end point, as well as by using a fuel injection amount after the predetermined oil degradation degree dispersion point when the fuel injection end point is set after the predetermined oil degradation degree dispersion point; and

accumulating the oil degradation value for the current performed fuel injection operation to thereby judge the oil degradation.

2. An engine oil degradation judging apparatus in which a signal from a sensor, for detecting a signal required for obtaining a fuel injection end point, is inputted, comprising:

a map storage portion for storing at least a first map that contains data for obtaining an oil degradation value for a current fuel injection operation based on a fuel injection end point when the fuel injection end point is set before a predetermined oil degradation degree dispersion point, and a second map that contains data for obtaining the oil degradation value for the current fuel injection operation based on the fuel injection end point, as well as on a fuel injection amount after the predetermined oil degradation degree dispersion point, when the fuel injection end point is set after the predetermined oil degradation degree dispersion point;

a current injection degradation value portion for obtaining the oil degradation value for the fuel injection operation from data contained in the first map storage portion or the second map storage portion for every fuel injection operation performed and for storing the same value;

a cumulative degradation value portion for cumulatively adding the oil degradation value of the current injection degradation value portion to obtain a cumulative degradation value every time the fuel injection operation ends and for storing the same value; and

an oil degradation judging portion for judging oil degradation based on the cumulative degradation value obtained by the cumulative degradation value portion so that a judgement signal may be outputted.

3. The engine oil degradation judging apparatus according to claim 2, wherein the oil degradation judging portion includes:

a residual lifetime ratio portion for calculating a residual lifetime ratio K(N) based on the formula;

4. The engine oil degradation judging apparatus according to claim 3, further comprising a display device of judgment results to display judgment results, and including an oil exchange alarm in response to a judgment output.

5. The engine oil degradation judging apparatus according to claim 2, further comprising a display device of judgement results to display judgement results, and including an oil exchange alarm in response to a judgement output.